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| Titel |
The implications of microbial and substrate limitation for the fates of carbon in different organic soil horizon types of boreal forest ecosystems: a mechanistically based model analysis |
| VerfasserIn |
Y. He, Q. Zhuang, J. W. Harden, A. D. McGuire, Z. Fan, Y. Liu, K. P. Wickland |
| Medientyp |
Artikel
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| Sprache |
Englisch
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| ISSN |
1726-4170
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| Digitales Dokument |
URL |
| Erschienen |
In: Biogeosciences ; 11, no. 16 ; Nr. 11, no. 16 (2014-08-25), S.4477-4491 |
| Datensatznummer |
250117561
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| Publikation (Nr.) |
 copernicus.org/bg-11-4477-2014.pdf |
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| Zusammenfassung |
| The large amount of soil carbon in boreal forest ecosystems has the
potential to influence the climate system if released in large quantities in
response to warming. Thus, there is a need to better understand and
represent the environmental sensitivity of soil carbon decomposition. Most
soil carbon decomposition models rely on empirical relationships omitting
key biogeochemical mechanisms and their response to climate change is highly
uncertain. In this study, we developed a multi-layer microbial explicit soil
decomposition model framework for boreal forest ecosystems. A thorough
sensitivity analysis was conducted to identify dominating biogeochemical
processes and to highlight structural limitations. Our results indicate that
substrate availability (limited by soil water diffusion and substrate
quality) is likely to be a major constraint on soil decomposition in the
fibrous horizon (40–60% of soil organic carbon (SOC) pool size variation), while energy limited
microbial activity in the amorphous horizon exerts a predominant control on
soil decomposition (>70% of SOC pool size variation).
Elevated temperature alleviated the energy constraint of microbial activity
most notably in amorphous soils, whereas moisture only exhibited a marginal
effect on dissolved substrate supply and microbial activity. Our study
highlights the different decomposition properties and underlying mechanisms
of soil dynamics between fibrous and amorphous soil horizons. Soil
decomposition models should consider explicitly representing different
boreal soil horizons and soil–microbial interactions to better characterize
biogeochemical processes in boreal forest ecosystems. A more comprehensive
representation of critical biogeochemical mechanisms of soil moisture
effects may be required to improve the performance of the soil model we
analyzed in this study. |
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